* Split out the arrow and progressbar in the indicatorOverlay for individual animation.
* Group icon and progressbar parts into addressable elements in a single download-icons.svg
MozReview-Commit-ID: KAn0gFqjKjc
This removes the arrowStyledIndicator killswitch and the associated ability for system add-ons to restore the previous design of the Downloads Indicator in the toolbar. The removal includes all the related code, styles, and strings. Based on the original patch by :rexboy.
MozReview-Commit-ID: 2OEBzPNzl0O
With this change two new attention states are introduced, "severe" and "warning",
along with the previous "success" and "no attention" states. "No attention" is
still a falsy value in order to mitigate any add-on compatibility issues.
"severe" and "warning states" now display an icon badge to the downloads button
(or the hamburger button if the downloads button is tucked away).
MozReview-Commit-ID: 3gc9Ji7zCXY
